Giant Chasm is a cratered area and its surrounding cave just north of Route 13. This area was created when a meteor crashed a long time ago. The meteorite was said to contain a monster which ate people. When you get into the centre of the area, the Giant Chasm flashfreezes and you can gain access to another cave, where the legendary Pokémon, Kyruem, dwells. In Black 2 & White 2, the plains of it get flattened by the landing of the Plasma Frigate